Higginson Island (23411)
Australia, Australasia
Site overview
KBA status: confirmed
Global KBA criteria: D1a
Year of last assessment: 2009
National site name: Higginson Island
Central coordinates: Latitude: -12.0650, Longitude: 136.8592
System: marine, terrestrial
Elevation (m): 0 to 10
Area of KBA (km2): 0.48186
Protected area coverage (%): 24.04
KBA classification: Global
Legacy site: Yes
Site details
Site description: This IBA consists of a chain of small islands running north from Nhulunbuy in Arnhemland. Higginson Island is a high rocky island with vines and grasses, at the end of the island chain, about 100 m x 60 m, Forlsche Rock is a small grassy rocky island to the south, East Bremer is a rocky and sandy island further south, from where a chain of rocky islets extend to South East Islet. The IBA also includes Veronica island to the west, which is a small vegetated coral rubble and rock island with a lighthouse. These are island refs S030, S031, S032, S033 and S085 in Chatto (2001).
Rationale for qualifying as KBA: This site qualifies as a Key Biodiversity Area of international significance that meets the thresholds for at least one criterion described in the Global Standard for the Identification of KBAs.
Additional biodiversity: Chatto (2001) made 10 counts on Higginson and also found 1000s of nesting Crested Terns (max 10,000+ birds), 100s of Common Noddies (max 300+ birds) - the only known breeding site in the Northern Territory - and 10s of nesting Silver Gulls. On East Bremer, Chatto made nine visits and recorded nesting Roseate Terns (maximum 2500 birds) on two out of three years when visits were made during the apparent nesting season. East Bremer and the rocky islets to the south also support up to 250 Bridled Terns, with another 400 Bridled Terns on South East islet. Veronica Island supported 1500 Roseate Terns one year in which they were missing from Higginson, and up to 2000 Bridled Terns (which may be additional to the Higginson totals). Forlsche Rock has had 200 Roseate Terns perhaps as an overspill from Higginson.
Other site values: Arnhemland ALT. Traditionally-owned land.
Habitats
| IUCN Habitat | Coverage % | Habitat detail |
|---|---|---|
| Marine Coastal/Supratidal | 100 |
Threats
Summary of threats to biodiversity at KBA: No known threats. The numbers of nesting seabirds should be monitored.
| Threat level 1 | Threat level 2 | Threat level 3 | Timing |
|---|---|---|---|
| Biological resource use | Fishing & harvesting aquatic resources | Unintentional effects: subsistence/small scale (species being assessed is not the target) [harvest] | Ongoing |
| Biological resource use | Hunting & collecting terrestrial animals | Motivation Unknown/Unrecorded | Only in the future |
| Invasive & other problematic species, genes & diseases | Problematic native species/diseases | Unspecified species | Only in the future |
| Pollution | Domestic & urban waste water | Type Unknown/Unrecorded | Ongoing |
| Human intrusions & disturbance | Recreational activities | Ongoing |
Additional information
References: Chatto, R. (1998) Seabird islands. No. 238. Higginson Islet, north-east Arnhem Land, Northern Territory. Corella. 22: 69-70. Chatto, R. (2001) The distribution and status of colonial breeding seabirds in the NT. Technical Report 70. Parks and Wildlife Commission of the Northern Territory, Palmerston. Harrison, L., McGuire, L., Ward, S. Fisher, A., Pavey, C., Fegan, M. and Lynch, B. (2009) An inventory of sites of international and national significance for biodiversity values in the Northern Territory. Department of Natural Resources, Environment, the Arts & Sport, Darwin, NT. Ward, S. and Harrison, L. (2009) Recognising sites of conservation significance for biodiversity values in the Northern Territory. Department of Natural Resources, Environment, the Arts & Sport, Darwin, NT.